Hi,
Check whether the bridge is grounded. Open the tremolo cavity and see whether a wire is soldered to the claw that holds the springs. If yes, take off the pickguard and see whether this wire is soldered to the back of a pot or to the ground connection at the output jack. If it is and you still do not notice a decrease in hum when you touch the strings your guitar may be pretty well shielded, and any noise you are hearing is magnetically induced hum of the single coils. There is nothing to change that unless you switch to noiseless pickups.
If there is no such wire or it is not soldered to the back of a pot or to the jack ground connection, install this wire.
Cheers Stephan